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Filter or Standard preamp?

Discussion in 'Pickups & Electronics [BG]' started by RHCP250, Apr 21, 2009.


  1. RHCP250

    RHCP250

    Nov 24, 2008
    Who here prefers a filter pre over a standard one? What are the advantages of one over the other? I only have experience with standard cut and boost ones, and cant find a filter one to try
     
  2. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    Aside from Alembic and ACG/East, I can't really think of any onboard filter-based preamps you could try. (Wal preamps are only available in Wals...)

    The two EQ styles just work differently. I've used filter-based preamps in my Wals for many years, so I'm used to them, but many people find them hard to use if they are accustomed to the standard cut/boost. Some sounds are very easy to get with filter-based EQs--particularly a wide range of darker or brighter tones--but you can't do other things that are very easy to accomplish with a straight cut/boost EQ, like boost the bass without affecting anything else.

    Mike
     
  3. Skelf

    Skelf

    Apr 15, 2005
    Moffat D&G Scotland
    Builder AC Guitars.
    Hi
    Much as Mike all ready points out. Filters do give you a wide range of sounds some which I think you would struggle to find on a standard cut/boost. This off course works both ways Mike's example being a good one.
    Couple of things to add. There is a learning curve to get the best from a filter set up if you come from the cut/boost way of doing things. It is not a steep curve but you need to spend a little time to get the best from it.
    Second and this is just my opinion I find filters to be very musical and to my ear really suit the bass particularly fretless bass..

    Alan
     
  4. RHCP250

    RHCP250

    Nov 24, 2008
    I see. I'd really like to try one out, but I dont want to drop 3 bills and find out I dont like it
     
  5. Greenman

    Greenman

    Dec 17, 2005
    Ontario Canada
    I have an Audere Zmode and an East J-Retro Deluxe and I forked out. Can't wait to try it with one MM 5.4 pickup:D
     
  6. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    However, while those are both great preamps, neither one is the kind of filter-based preamp the OP is asking about.

    Mike
     
  7. Greenman

    Greenman

    Dec 17, 2005
    Ontario Canada
    I'm aware of that. :)
     
  8. Hoover

    Hoover Banned

    Nov 2, 2007
    New York City
    Most of my experience with "filter-based EQs" (sic) is with the Alembic SF-2, an outboard unit similar (though not identical) to the onboard filter-based EQ on an Alembic Series II bass...and if that's at all representative of how they work, it's actually fairly easy to "boost the bass without affecting anything else" ...specifically because the output of the filters are in parallel with the dry (unfiltered) signal, and because they're phase-accurate. Simply set the LPF to a fairly low fc (say, 100Hz) and increase its output relative to the dry signal, and voila! you increase the bass content.

    I just installed an ACG EQ-02 in my Modulus and have my first gig with it tonight, so I'll see whether that works the same way or if I'm completely full of schidt! The key is the parallel mixing; if no unfiltered signal is available in the final mix, all bets are off...though if you can set the LPF & HPF cutoffs to the same fc, you should then be able to adjust their two outputs like a giant Bass/Treble "tilt" control.
     
  9. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    Hoover,

    I can tell you (from many years of experience with Wals and a few Alembics) that it doesn't work that way. Most filter-based onboard preamps--including the ones in just about any Alembic lower than the Series II--are lowpass only, and if there are two filters they generally are one per pickup, with no "parallel" mixing of the unfiltered signal. You set the cutoff frequency as high or low as you want, to cut off a wider or narrower range of treble frequencies, then you have the option add a boost just below the cutoff frequency. The only way to boost bass frequencies is to turn the cutoff frequency down to cut out anything above the frequency range you want to boost.

    Mike
     
  10. Hoover

    Hoover Banned

    Nov 2, 2007
    New York City
    ^^^ Yeah, I wasn't even thinking about Alembics other than the Series models; don't think I even knew that Essences & Distillates etc used filter-based preamps.

    I spent my first extended session with the ACG EQ-02 filter-based preamp last night, and while the two filters (LP & HP) are in parallel & their outputs are mixed, there is no unfiltered signal also in parallel and also available to mix with the filtered signals (like there is on the Alembic SF-2).

    However, I did find a few settings where simply turning up the Peak Overshoot of the LPF would effectively "boost the bass without affecting anything else" ...although to be fair, it also thickened up the lower-midrange a bit as well.
     
  11. RHCP250

    RHCP250

    Nov 24, 2008
    If I were to get an ACG02 filter pre, would opening it up for all frequencies, but not boosting the cut-off give a "flat" setting? Also do you think filters are more versitile? Is a filter pre more aggressive than a plain one on average?
     
  12. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    Alan could tell you for sure, but my impression is that opening the preamp all the way up with no boost gives essentially a flat setting. There may be a little bit of top-end attentuation for the very highest frequencies, since the top frequency for the bass (lowpass) filter is 6.3kHz, but the sweep of the treble stack may compensate for that even without any boost.

    I'm not sure I'd call filters "more versatile"--there are some sounds you can get a lot more easily with filter preamps than with regular boost/cut preamps, but the reverse is also true. They're not especially "aggressive" in and of themselves, either--I suspect people get that impression because the Wal preamp is filter-based, but I'd say the Wal's aggressive tone has more to do with the pickups. On the other hand, Alembics are generally fairly smooth sounding, and they also use filter-based preamps.

    Mike
     
  13. RHCP250

    RHCP250

    Nov 24, 2008
    I like to be able to use one bass for the most part, and just twist some knobs to get different sounds. I was thinking of putting one in my spector, that way i can get the gnarly spector tone, but also tone it down for more mellow songs.
     
  14. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    I think it would work well for that. The lowpass filter makes it easy to smooth out very bright, aggressive pickups, then bring back in some clarity with the highpass treble stack if you need to.

    Mike
     
  15. Skelf

    Skelf

    Apr 15, 2005
    Moffat D&G Scotland
    Builder AC Guitars.
    Hi
    There are several Spector's with the pre-amp in it. It seems to go down pretty well. If you go to Basschat in the UK and search for ACG or Spector you will find a few threads on the subject.


    Lowpass filter fully open no boost and the high pass with the gain fully off is as close to flat as possible.

    Alan
     
  16. RHCP250

    RHCP250

    Nov 24, 2008
    This is good news, I might be trying one of these out soon.
     
  17. MarcusPocus

    MarcusPocus

    Aug 28, 2008
    Allen, Tx
    I tried the filter from ACG without hearing it. I just read a ton of reviews along with a description of how it works. I stuck it in my Jazz V standard 08. It has Nordstrands so the passive tone was wicked good. I was reluctant, but I must tweak. Anyway, the install was incredibly easy. It sounded like my bass at first. I was happy that it didn't mutate the sound. Then You start to twisting the knobs. Whoa!! You can drastically change the tone. It did take a few days to find the stuff I normally like. Now, I can get there on the fly. I never really understood when people would describe a pre as musical until I used this. When playing, every note seems to pop out clear and articulate. Even triads played way down in the lower register ring clear when normally that would be a muddy mess. Playing with a band, the bass really fits in nicely.

    And, I had a question so I emailed Alan and his replies were quick and useful. I would imagine that if I had any problems finding support would never be an issue. Great product Man!
     
  18. RHCP250

    RHCP250

    Nov 24, 2008
    One last quick question. I like the sound of my spector set flat, its pretty aggressive, and I also like the sound when I dime the pre-amp (which I rarely do), because its super aggressive. Can the ACG dial in the aggressive tone I like my spector for?
     
  19. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    I expect the ACG can dial in a very aggressive tone. I doubt it's the *same* aggressive tone you get when turning your preamp up all the way, though, because it won't be boosting the same frequencies. You can't easily do the "scooped" sound you get with individual treble and bass boosts on the Tonepump or Aguilar OBP-1 preamps, for instance.

    Mike
     
  20. RHCP250

    RHCP250

    Nov 24, 2008
    I see. Thanks for the replies!
     

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